WO2003011542A1 - Panneaux osb basse densite et leurs procedes de fabrication - Google Patents

Panneaux osb basse densite et leurs procedes de fabrication Download PDF

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Publication number
WO2003011542A1
WO2003011542A1 PCT/CA2002/001198 CA0201198W WO03011542A1 WO 2003011542 A1 WO2003011542 A1 WO 2003011542A1 CA 0201198 W CA0201198 W CA 0201198W WO 03011542 A1 WO03011542 A1 WO 03011542A1
Authority
WO
WIPO (PCT)
Prior art keywords
flakes
resin
board
mat
wood flakes
Prior art date
Application number
PCT/CA2002/001198
Other languages
English (en)
Inventor
Andrew T. Go
Elizabeth Cacchione
Original Assignee
Nexfor Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nexfor Inc. filed Critical Nexfor Inc.
Priority to CA002455904A priority Critical patent/CA2455904A1/fr
Publication of WO2003011542A1 publication Critical patent/WO2003011542A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
    • B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
    • B27N3/04—Manufacture of substantially flat articles, e.g. boards, from particles or fibres from fibres
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/25—Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
    • Y10T428/253—Cellulosic [e.g., wood, paper, cork, rayon, etc.]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
    • Y10T428/268—Monolayer with structurally defined element

Definitions

  • the present invention relates to a method of manufacturing panels or boards composed of wood material. More specifically, the invention provides a method of manufacturing oriented strand boards of lower density.
  • Wood based construction is very popular in North America and other parts of the world. In such construction, wood boards or panels are often used in sheathing the building or for other structural purposes. Such panels, are commonly provided in 4' x 8' sheets. Plywood is one example of such a panel. Plywood is formed from veneer sheets of wood peeled off from logs and laminated together to form the panels. Plywood panels have densities almost equivalent to that of the wood itself and high strength characteristics. However, the cost of plywood is high due to the amount of wood material used in its formation.
  • OSB oriented strand boards
  • OSB panels are formed by layering strands, or flakes of wood mixed with a resin or binder and subjecting the layers to heat and pressure. Since OSB panels are made from pieces of wood that are chipped off from logs, there is less waste material as compared to plywood and, therefore, such panels have a lower material cost.
  • one drawback that has been found lies in the increased density of such boards due to the amount of resin required to achieve the required strength characteristics.
  • OSB products are provided in the following US Patents: 4,246,310 (Hunt et al.); 4,610,913 (Barnes); 5,506,026 (Iwata et al.); and, 5,736,218 (Iwata et al.).
  • the typical density of an OSB panel is in the range of 38 to 40 lbs/ft 3 (pcf) and is considerably higher than that of plywood, which is typically in the range of 28 to 32 pcf.
  • the weight of OSB panels is also considerably greater, which causes various problems when such boards are used in construction.
  • the prior art such as that mentioned above, describes various attempts to provide a low density OSB, the resulting board often has reduced structural integrity and strength.
  • the present invention provides a method for producing a "low density" OSB while still preserving the desired strength characteristics.
  • the present invention provides a method of producing an oriented strand board panel comprising: a) providing first wood flakes having a first thickness; b) providing second wood flakes having a second thickness, wherein the second thickness is greater than the first thickness; c) adjusting the moisture content of the first wood flakes to between 6 and 12 wt% and of the second wood flakes to less than 9 wt%; d) mixing the flakes with a resin; e) forming a first mat with the first wood flakes; f) forming a second mat, over the first mat, with the second wood flakes; g) forming a third mat, over the second mat, with the first wood flakes, whereby a three layer composite mat is formed; and h) pressing and heating the layers of mats in a press.
  • the invention provides an oriented strand board comprising: - two surface layers composed of first wood flakes; - a core layer composed of second wood flakes, the core layer being between and laminated to the two surface layers; wherein: - the density of the board is less than about 35 pounds/ft 3 ; - the thickness of the core layer comprises about 1/3 of the total thickness of the board; - the first wood flakes are about 3" - 6" long, 1" - 2" wide, and 0.018" - 0.025” thick; and, - the second wood flakes are about 3" - 6" long, 1" - 1.5" wide, and 0.025" - 0.035" thick.
  • Figure 1 is a cross sectional elevation view of an OSB panel according to an embodiment of the present invention.
  • FIG. 1 An OSB panel according to the present invention is illustrated in Figure 1. It will be understood that Figure 1 is used solely to illustrate the invention and that it is not intended to limit or reflect the scale or dimensions of the board or the components thereof.
  • the board 5 is comprised of at least 3 layers.
  • the board 5 includes a core layer 6 that lies between a pair of face layers 2 and 4.
  • Each of the facing layers 2 and 4 and the core layer 6 are comprised of wood chips or flakes 8 and 10, respectively.
  • the flakes 8 of the face layers 2 and 4 are thinner than the flakes 10 of the core layer 6.
  • the flakes 8 of the faces 2 and 4 are slightly longer than those 10 of the core 6.
  • the flakes of the faces have a length of approximately 5" - 5.75" while that of the core flakes is approximately 4" - 4.5".
  • the flakes of the OSB panels have the following general dimensions:
  • the flakes 8 in the face layers 2 and 4 are preferably oriented so that the lengths of the flakes are generally aligned with the length of the board.
  • the flakes 10 are preferably aligned so that the lengths are generally perpendicular to that of the flakes of the face layers.
  • OSB panels made according to the present invention have densities that are generally less than 35 pcf (pounds per cubic foot) and, generally, between 28 and 32 pcf.
  • the OSB of the invention is made from flakes of Aspen, as is typically used in the art, or other woods of similar characteristics. It will be understood that the above density values of the boards of the invention are based on the use of Aspen flakes and that slight variations will be encountered when flakes of other wood are used due to the inherent difference in the densities of the wood.
  • the total thickness of the OSB according to the present invention comprises 30% - 35%) of the core layer 6 and 65% - 70% of the two face layers.
  • the core layer 6 makes up about 36% of the total thickness of the board, while the face layers make up 64% of same (i.e. each of the face layers comprises 32% of the total thickness).
  • the preferred total thickness of the OSB is 7/16", which is the common thickness of 4'x8' boards used in construction. It will be understood, however, that the thickness of the board can be varied if needed.
  • the binder or resin used to adhere the various flakes of the board are generally known in the art.
  • the resin used in the present invention is either MDI (polymeric methylene di-isocyanate) or PF (phenol formaldehyde).
  • the PF resin may be provided in liquid (LPF) or powder (PPF) form or a combination of both.
  • MDI polymeric methylene di-isocyanate
  • PF phenol formaldehyde
  • the PF resin may be provided in liquid (LPF) or powder (PPF) form or a combination of both.
  • the resin is added in liquid form and the preferred amount of resin is 2% - 4.5% (wt% based on weight of wood flakes) and, more preferably 2.5% - 3%.
  • the preferred amount of resin is 2% - 6% (wt%), and, more preferably 6%.
  • the PF resin is provided in both powder and liquid forms in the following proportions: % PPF and V LPF. Therefore, as will be understood, if the total amount of PF added is 6%, the liquid component of PF comprises 1.5% and the powder component comprises 4.5% of the total.
  • the flakes 8 and 10 of the OSB will also have different moisture contents, which will depend upon the resin that is used.
  • the moisture contents of the flakes are as follows:
  • the difference between the surface and core moisture content should preferably be at least 3%.
  • a wax is also added to the flakes to impart water repellency.
  • Such waxes are known in the art.
  • the resin is added as 3 A powder (PPF) and ! 4 liquid (LPF). Further, in the preferred embodiment, and where PF is used, the liquid component is added before the powdered component. The minimal amount of liquid PF resin is used to retain the powder component on the flakes. The present inventors have found that where only powder PF resin is applied the board's bending strength is impaired. This is illustrated in the examples below.
  • the pressing is conducted using a "Fast Close” method wherein, as is known in the art, the press is closed rapidly.
  • the press is "fast closed” in preferably less than 30 seconds and typically 15 to 30 seconds.
  • the press closing times will vary for boards of other thicknesses. It is known in the art that a fast close method results in higher bending strengths of the boards. However, it is also know in the art that such a method also compromises the internal bond (IB) strength between the flakes.
  • IB internal bond
  • the method of the present invention offers an advantage in that there is no reduction in IB strength even though a "fast close" method is used. It is believed that the reason for this benefit in maintaining IB strength stems from the higher resin coverage of the thicker flakes. In other words, the reduced surface area to weight ratio of the flakes (due to the use of thicker flakes) of the present invention leads to an increase in resin coverage. Thus, the use of thicker flakes in the present invention leads to an added benefit by allowing the use of the fast close press method while retaining desired IB strength values. In accordance with the preferred embodiment of the present invention, IB values of at least 40 psi are achieved.
  • the press used for forming the boards is conventionally known in the art.
  • the press typically includes opposing platens that are heated to a desired temperature. Both the temperature and pressing (or “cooking") time will depend on the resin used. For example, the following conditions are preferred for the present invention:
  • the layers of flakes are sprayed with a fine mist containing 0.8% to 1.5% water, prior to pressing.
  • the mat is covered with 50 - 75 g/m 2 of water. Such a spraying helps to develop the internal bond of the panel thereby reducing the amount of resin needed to form the board. In the result, the density of the board is also reduced.
  • Aspen logs were waferized to specific flake dimensions for the core and surface layers.
  • the face layers consisted of wafers which were 5.75" long by 0.020" - 0.025" thick by no more than 1" - 2" wide, while the core layer was composed of wafers which were 4.5" in length by 0.030" - 0.035" thick by 1" - 1.5" wide.
  • the water content in the flakes was adjusted to 9% to 12% in the face and 6% to 9% in the core layers wherein the percentage of water was measured on a weight basis based on the weight of the wood material. A moisture content differential of at least 3% was maintained between the face and core layers.
  • the flakes were prepared by: (1) adjusting the water content as indicated above; (2) adding a wax; (3) adding the liquid PF component; and (3) adding the powder PF component. The resin components were added through a series of spinning discs. This enabled obtaining a tight resin distribution, which is important in reducing density with a powdered phenolic resin.
  • the panel was formed in 3 cross-oriented layers.
  • the face layers comprised 65- 75% of the total thickness of the mat, while the core layer comprised the remaining 25-35%.
  • the mat was sprayed with 0.8% to 1.5% water in a fine mist. This was found to assist in developing the internal bond of the panel and to reduce resin usage.
  • the pressing strategy which is believed to be important in reducing panel density, was a "fast close" method wherein the press was closed in 15-30 seconds for a 7/16" panel. Following this, a press, or cook time of 120 seconds was used for PF, or 45-55 seconds for MDI at a press temperature of 230°C. It will be understood that the required press time will vary depending upon the press temperature. Therefore, at lower temperatures, a longer press time will be required. For example, in the case of MDI resin, the press time would be extended to 80 seconds for a press temperature of 200°C.
  • Table 1 7/16" x 4' x 8' panel production at 210 °C: Face/Core ratio: 64/36
  • MOE - modulus of elasticity (measured in perpendicular (perp) or parallel (par) directions).
  • Standard refers to generally acceptable standards for boards.
  • Table 2 Effect of Temperature and Moisture Content on Press Time The following tests were conducted to investigate the effect of press temperature and moisture content of the furnish on the press time.
  • a sample panel having dimensions 7/16"X 3'X3' was used, each of which had a density fixed at 38 lbs/ft 3 .
  • the resin used was MDI in the amount of 3 wt%.
  • the face/core ratio of each panel was 50/50 and for each the flakes were not oriented.
  • the furnish was wetted with water in the amount of 0.8 wt% prior to pressing.
  • the following data provides information on the effect of applying water on the furnish prior to pressing (i.e. as a spray as described above).
  • the density of each panel was fixed at 35 lb/ft 3 and 2.5 wt% MDI resin was used.
  • the press temperature was set at 215 °C and the total press time was 130 seconds.
  • a Face/Core ratio of 64/36 was used and wherein the moisture content for the face and core layers was adjusted to 8% and 6%, respectively.
  • the first column indicates the amount of water added based on the weight of the wood flakes.
  • Each of the panels was of the same size as in table 2.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Dry Formation Of Fiberboard And The Like (AREA)

Abstract

Procédé servant à fabriquer un panneau OSB et consistant à produire un stratifié de nappes de copeaux de bois recouvert par une résine et à comprimer ce stratifié à la chaleur. Ce stratifié est composé d'une couche centrale à laquelle adhèrent deux couches superficielles. Les copeaux sont agglomérés par une résine composée de phénol formaldéhyde (PF) ou méthylène di-isocyanate (MDI) polymère.
PCT/CA2002/001198 2001-08-02 2002-08-01 Panneaux osb basse densite et leurs procedes de fabrication WO2003011542A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA002455904A CA2455904A1 (fr) 2001-08-02 2002-08-01 Panneaux osb basse densite et leurs procedes de fabrication

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA2,354,640 2001-08-02
CA002354640A CA2354640A1 (fr) 2001-08-02 2001-08-02 Panneaux a copeaux orientes legers et methodes de fabrication

Publications (1)

Publication Number Publication Date
WO2003011542A1 true WO2003011542A1 (fr) 2003-02-13

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PCT/CA2002/001198 WO2003011542A1 (fr) 2001-08-02 2002-08-01 Panneaux osb basse densite et leurs procedes de fabrication

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Country Link
US (1) US20030113530A1 (fr)
CA (1) CA2354640A1 (fr)
WO (1) WO2003011542A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110434954A (zh) * 2019-08-31 2019-11-12 广东始兴县华洲木业有限公司 一种零甲醛轻质颗粒板的制备工艺

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2354909A1 (fr) * 2001-08-08 2003-02-08 Liheng Chen Panneau a copeaux orientes legers
US6767490B2 (en) * 2002-10-07 2004-07-27 Nexfor Inc. Low density oriented strand boards
US20070111019A1 (en) * 2005-11-04 2007-05-17 Ainsworth Lumber Co., Ltd. Methods of manufacturing engineered wood products
US9440418B2 (en) 2012-08-13 2016-09-13 Weyerhaeuser Nr Company Thermally insulating low density structural wooden composite
CN103072172B (zh) * 2012-12-13 2013-12-11 江苏快乐木业集团有限公司 一种基于高密度定向刨花板的箱板及其加工方法
US20170151758A1 (en) * 2015-12-01 2017-06-01 Norbord Inc. Oriented Strand Board
JP7042560B2 (ja) * 2017-06-02 2022-03-28 大倉工業株式会社 木質ボード及びその製造方法

Citations (4)

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Publication number Priority date Publication date Assignee Title
US5470631A (en) * 1990-04-03 1995-11-28 Masonite Corporation Flat oriented strand board-fiberboard composite structure and method of making the same
US5506026A (en) * 1993-05-31 1996-04-09 Yamaha Corporation Wood board and a flooring material made therefrom
DE4439271A1 (de) * 1994-09-29 1996-06-13 Dieffenbacher Gmbh Maschf Verfahren und Anlage zur kontinuierlichen Herstellung einer Mehrschichtholzplatte
WO2000029180A1 (fr) * 1998-11-13 2000-05-25 Holzindustrie Preding Gesellschaft Mbh Element de construction en bois

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US4246310A (en) * 1979-04-06 1981-01-20 The United States Of America As Represented By The Secretary Of Agriculture High performance, lightweight structural particleboard
US4364984A (en) * 1981-01-23 1982-12-21 Bison-Werke, Bahre & Greten Gmbh & Co., Kg Surfaced oriented strand board
US4610913A (en) * 1986-02-14 1986-09-09 Macmillan Bloedel Limited Long wafer waferboard panels
CA2039559C (fr) * 1990-04-03 1996-11-19 John T. Clarke Structure composite a panneaux a copeaux orientes et methode de fabrication connexe
US6479127B1 (en) * 1999-10-12 2002-11-12 J.M. Huber Corporation Manufacture of multi-layered board with a unique resin system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5470631A (en) * 1990-04-03 1995-11-28 Masonite Corporation Flat oriented strand board-fiberboard composite structure and method of making the same
US5506026A (en) * 1993-05-31 1996-04-09 Yamaha Corporation Wood board and a flooring material made therefrom
DE4439271A1 (de) * 1994-09-29 1996-06-13 Dieffenbacher Gmbh Maschf Verfahren und Anlage zur kontinuierlichen Herstellung einer Mehrschichtholzplatte
WO2000029180A1 (fr) * 1998-11-13 2000-05-25 Holzindustrie Preding Gesellschaft Mbh Element de construction en bois

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110434954A (zh) * 2019-08-31 2019-11-12 广东始兴县华洲木业有限公司 一种零甲醛轻质颗粒板的制备工艺

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Publication number Publication date
US20030113530A1 (en) 2003-06-19
CA2354640A1 (fr) 2003-02-02

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